In the operation of a contracting business there are many instances where a front-end loader is useful in lifting and carrying large objects such as stones, bundles of brush, logs, and the like. For that purpose, a front-end loader with a bucket has sufficient strength to handle such large heavy objects, but, because they are so awkward, it is difficult to retain them on the bucket. My U.S. Pat. No. 4,155,473 which issued on May 22, 1979 discloses a hydraulically-actuated clamp arm operating with the bucket in handling awkward objects. The mechanism shown in that patent has the advantage that it can be stored along the top edge of the bucket when not in use. However, there has been a tendency recently to construct the buckets of front-end loaders so that they have increased height without a commensurate increase in width. This is because it has become desirable to make front-end loaders larger and stronger and, therefore, capable of carrying larger amounts of material in the bucket. However, the width of the bucket is limited by the ability to transport the loader over highways where there are certain legal limits to the width of a vehicle. For that reason, the only direction that increase in capacity of buckets can take is in the vertical direction, i.e., the distance between the bottom horizontal edge and the top horizontal edge. When one attempts to use the device shown in my above-mentioned patent on such narrow but high buckets, that problem arises that, if the clamp arm is made long enough to reach from the top edge to the bottom edge of the bucket, it extends outwardly of the bucket and presents a dangerous situation if one attempts to store it along the top edge of the bucket. In addition, it is wider than the mentioned legal vehicle width limits. Furthermore, if the clamp arm extends beyond the side of the bucket, it is likely to engage trees, buildings, boulders, etc. and create the possibility of severe damage to the arm and its associated parts. It would be understood that only half of the width of the bucket is available for storing the arm, so that the problem described above arises when the height of the bucket is greater than one-half of the width. These and other difficulties experienced with the prior art devices have been obviated in a novel manner by the present invention.
It is, therefore, an outstanding object of the invention to provide material handling apparatus for use on a front-end loader bucket, including a clamp arm which is retractable for storage but is extensible for use.
Another object of this invention is the provision of clamp arm for use on a bucket where the height of the bucket is greater than one-half of its width.
A further object of the present invention is the provision of an extensible clamp arm for use on a bucket, wherein the hydraulic actuator is not exposed to dirt and other deteriorating effects during operation.
It is another object of the instant invention to provide a clamp arm for use on material handling apparatus, which arm is simple and rugged in construction, which can be inexpensively manufactured from readily obtainable materials, and which is capable of a long life of useful service with a minimum of maintenance.
A still further object of the invention is the provision of an extensible clamp arm with no delicate external parts.